Crawl space ventilation device and method

ABSTRACT

A device and method for providing ventilation to an interior portion of a crawl space. The proposed blower has a substantially cylindrical housing and a hollow interior. A fan is mounted in the hollow interior of the housing, and is configured to draw air into and propel air out of the housing. The blower is suspended from the floor joists by chain, wire, synthetic cable or the like so that the blower hangs in the crawl space between the floor of the house and the ground. In the preferred embodiment, the attachment means for hanging the blower from the floor joists is provided on both ends of the housing. The attachment means are preferably non-rigid so that they dampen the vibrational energy transmitted to the floor joist by the blower.

BACKGROUND OF THE INVENTION

1. Field of the Invention.

This invention relates to the field of mold and wood-decaying fungi control. More specifically the present invention comprises a ventilation device and method for ventilating a crawl space and preventing the growth of mold and wood-decaying fungi therein.

2. Description of the Related Art.

Crawl spaces have been and remain a popular building option for houses. Crawl spaces provide many advantages over slab foundations including superior access to the house's electrical, plumbing, and HVAC systems and increased separation of the house's wooden structure from the ground and wood-destroying pests.

A typical crawl space is illustrated in FIG. 1. A house's crawl space is surrounded by crawl space walls 38. Crawl space walls 38 are generally constructed of cinder blocks and mortar on the interior and brick masonry on the exterior. Floor joists 14 span the top of the crawl space and cross from one crawl space wall to a crawl space wall on the opposite side of the house. The floor and walls of the house are constructed above and fastened to floor joists 14. Interior 40 of the crawl space is accessible through crawl space access point 42. Because crawl space walls 38 are generally two to four feet high, an individual entering the crawl space must generally move around the crawl space on hands and knees.

Dampness is a major concern in crawl spaces. Because, crawl space walls 38 surround the crawl space, moisture tends to accumulate in the crawl space. Vents 44 are commonly provided in crawl space walls 38 to allow moisture to escape. Although vents 44 may be effective for some houses in some regions, the growth of mold and wood-decaying fungi in crawl spaces has been an ongoing problem in the industry. Molds and wood-decaying fungi can severely damage floor joists 14 and the structure of a house. If the damage is not noticed at an early stage, a homeowner may be forced to pay substantial costs for repair.

The onset of mold and wood-decaying fungi is most commonly observed in the far interior portions of a crawl space. For larger houses, the ventilation provided by vents 44 may not be sufficient to evacuate the moisture from the interior portions of the crawl space that are furthest from crawl space walls 38.

Wood is a hygroscopic material, which means it takes on and gives off water to balance out with its surrounding environment. Accordingly, floor joists 14 will absorb moisture in the air as the air's moisture content increases. When wood attains a moisture content of approximately 28 percent, the cells or fibers of the wood will not take in any more water. At this stage, the wood has attained a state of fiber saturation. Any water that is absorbed by the wood after the state of fiber saturation is held in the cavities between the cells. This water is often referred to as “free water.” Free water provides a fertile breeding ground for mold and wood-decaying fungi to propagate.

Accordingly, it would be desirable to provide a device and method to control the moisture content of crawl spaces, particularly the portions of the crawl space furthest from the crawl space walls.

BRIEF SUMMARY OF THE INVENTION

The present invention comprises a device and method for providing ventilation to an interior portion of a crawl space. The proposed blower has a substantially cylindrical housing and a hollow interior. A fan is mounted in the hollow interior of the housing, and is configured to draw air into and propel air out of the housing. The blower is suspended from the floor joists by chain, wire, synthetic cable or the like so that the blower hangs in the crawl space between the floor of the house and the ground. In the preferred embodiment, the attachment means for hanging the blower from the floor joists is provided on both ends of the housing. The attachment means are preferably non-rigid so that they dampen the vibrational energy transmitted to the floor joist by the blower.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a perspective view, showing a prior art crawl space with vents.

FIG. 2 is a perspective view, showing the present invention.

FIG. 3 is a section view, showing the present invention.

REFERENCE NUMERALS IN THE DRAWINGS

-   10 hanging blower 12 crawl space -   14 fan housing 16 exhaust barrel -   18 intake barrel 20 screen -   22 screen clamp 24 ground -   26 hanging chain 28 floor -   30 electrical cord 32 impeller -   34 motor mount 36 motor -   38 crawl space walls 40 interior -   42 crawl space access point 44 vents

DETAILED DESCRIPTION OF THE INVENTION

The present invention is illustrated in FIG. 1. Hanging blower 10 generally includes a substantially cylindrical housing with a fan (not shown in FIG. 1) mounted within the hollow interior of the housing. The housing has three principal components—exhaust barrel 16, fan housing 14, and intake barrel 18. The fan is mounted within fan housing 14 and is configured to draw air into intake barrel 18 of the housing and propel air out of exhaust barrel 16 of the housing. Screen 20 is provided on each end of the housing and prevents objects from being pulled into the housing when the fan is activated. Screen clamp 22 is used to attach each screen 20 to an end of the housing. This feature allows the user to easily replace screen 20 or remove screen 20 for cleaning.

Hanging blower 10 is preferably installed in the interior portion of a crawl space where the air is stagnant, moisture content is high, or where the presence of mold or wood-decaying fungi has been observed. Hanging blower 10 is suspended between floor 28 and ground 24 within crawl space 12 by hanging chain 26. In the preferred embodiment, a pair of hanging chains 26 are provided on both ends of the housing. Although linked chains are illustrated in FIG. 1, wire, synthetic cable and other non-rigid attachment mechanisms may be used to hang hanging blower 10 from floor joists 14. Chains, wire, and synthetic cable are all good choices for attachment mechanisms because they tend to dampen the vibrational energy transmitted to floor joist 14 by hanging blower 10. This feature enables the fan to run silently without disrupting the occupants of the house.

Electrical cord 30, which provides power to the fan, may be fastened to floor joist 14 and connected to an appropriate power source. Hanging blower 10 may be further equipped with controllers for allowing the fan to be periodically activated and deactivated without manual intervention. For example, a timer may be electronically connected between the power source and the fan. The timer may activate the fan to run for a period of time. It has been observed that the optimal run time is between approximately one hour and twelve hours, with three hours to six hours being the most preferred. In place of or in addition to the timer, a humidistat may also be electronically connected to the fan. The humidistat may be configured to detect moisture content in the air and activate the fan when the moisture content of the air exceeds a threshold. For example, the humidistat may activate the fan when the moisture content in the air exceeds 20%.

Exhaust barrel 16 functions to concentrate the flow of air propelled by the fan so that the air is projected a long distance away from the fan and the interior portion of crawl space 12. To accomplish this objective, exhaust barrel 16 is preferably one to three feet in length, with a most preferred length of 16 to 30 inches. If the exhaust barrel is too short, moisture-rich air will recirculate in the area around hanging blower 10 and will not properly ventilate the crawl space.

A section view, illustrating the internal components of hanging blower 10 is provided in FIG. 3. The fan is held in the interior of fan housing 12 by motor mount 34. Motor mount 34 spans the interior of fan housing 12 and supports the weight of motor 36. Motor 36 drives impeller 32, causing impeller 32 to rotate within fan housing 12.

Fan sizing is important in order to balance the ventilation needs for the crawl space while minimizing the noise of the ventilation system. If the fan is too small, an insufficient amount of ventilation will be provided. If the fan is too large, the fan will be unnecessarily loud. In order to minimize noise while providing adequate ventilation, hanging blower 10 preferably is configured to move a volume of air through its housing at a rate of 400 to 800 cubic feet per minute, with a most preferred rate of 450 to 600 cubic feet per minute. Although impeller 32 may be any size, it has been observed that impellers with diameter sizes of eight to twelve inches are particularly effective.

The preceding description contains significant detail regarding the novel aspects of the present invention. It should not be construed, however, as limiting the scope of the invention but rather as providing illustrations of the preferred embodiments of the invention. As an example, hanging blower 10 may be suspended from floor joists 14 by any number of attachment mechanisms. Such a variation would not alter the function of the invention. Thus, the scope of the invention should be fixed by the following claims, rather than by the examples given. 

1. A device for providing ventilation to an interior portion of a crawl space comprising: a. a blower including i. a substantially cylindrical housing having a first end, a second end, a medial section therebetween, and a hollow interior; ii. a fan mounted in said hollow interior of said housing proximal said medial section, said fan configured to draw air into said first end of said housing and propel air out of said second end of said housing; iii. a first attachment means for hanging said blower from a floor joist, said first attachment means proximal said first end; iv. a second attachment means for hanging said blower from a floor joist, said second attachment means proximal said second end; and b. wherein said first attachment means and said second attachment means together are configured to suspend said blower within said interior portion of said crawl space; c. wherein said first attachment means and said second attachment means each are non-rigid and are configured to dampen the vibrational energy transmitted to said floor joist by said blower.
 2. The device of claim 1, further comprising a screen, said screen attached to said housing around said first end.
 3. The device of claim 1, wherein said first attachment means comprises a material selected from a group consisting of: a. chain, b. wire, c. synthetic cable, and d. combinations thereof.
 4. The device of claim 1, wherein said housing comprises an exhaust barrel between said fan and said second end.
 5. The device of claim 2, wherein said housing comprises an exhaust barrel between said fan and said second end.
 6. The device of claim 1, said fan further comprising an impeller, said impeller having a diameter of approximately 8 inches to 12 inches.
 7. The device of claim 1, said blower configured to move a volume of air through said housing at a rate of 400 cubic feet per minute to 800 cubic feet per minute.
 8. The device of claim 7, said blower configured to move a volume of air through said housing at a rate of 450 cubic feet per minute to 600 cubic feet per minute.
 9. The device of claim 1, further comprising a timer configured to periodically activate said deactivate said fan.
 10. The device of claim 9, wherein said fan is activated for a period of time of approximately 1 to 12 hours.
 11. The device of claim 1, further comprising a humidistat, said humidistat configured to detect moisture content in the air and activate said fan when said moisture content of said air exceeds a threshold.
 12. A method for providing ventilation to an interior portion of a crawl space, said crawl space between the floor of a house and a ground, comprising the steps of: a. obtaining a blower, said blower including i. a substantially cylindrical housing having a first end, a second end, a medial section therebetween, and a hollow interior; ii. a fan mounted in said hollow interior of said housing proximal said medial section; said fan configured to draw air into said first end of said housing and propel air out of said second end of said housing; b. entering said crawl space with said blower; c. suspending said blower from a floor joist in said interior portion of said crawl space between said floor and said ground.
 13. The method of claim 12, wherein said blower is suspended by an attachment means, said attachment means being non-rigid and configured to dampen the vibrational energy transmitted to said floor joist by said blower.
 14. The method of claim 12, said blower further comprising a screen, said screen attached to said housing around said first end.
 15. The method of claim 13, wherein said attachment means comprises a material selected from a group consisting of: a. chain, b. wire, c. synthetic cable, and d. combinations thereof.
 16. The method of claim 12, wherein said housing comprises an exhaust barrel between said fan and said second end.
 17. The method of claim 12, said fan further comprising an impeller, said impeller having a diameter of approximately 8 inches to 12 inches.
 18. The method of claim 12, said blower configured to move a volume of air through said housing at a rate of 400 cubic feet per minute to 800 cubic feet per minute.
 19. The method of claim 12, said blower further comprising a timer configured to periodically activate said deactivate said fan.
 20. The method of claim 12, said blower further comprising a humidistat, said humidistat configured to detect moisture content in the air and activate said fan when said moisture content of said air exceeds a threshold. 